In industrial countries, the third most frequent cause of death is lung emboli. Ten percent of patients with acute lung emboli die from heart failure. Dissolution by medicine of the embolus (thrombolysis) takes hours. The patient often dies before a hemodynamic improvement occurs. Operational removal of the embolus in accordance with the so-called Tendelenburg operation entails a comparatively high rate of mortality.
With a combined treatment comprising mechanical destruction of lung emboli and a subsequent selective thrombolysis of the resulting fragments, it has in some cases been possible to obtain promising treatment results. In this case, the fragmentation of an embolus took place by manipulation with diagnostic standard pulmonary catheters. Such a catheter is advanced by means of a guide wire past an embolus towards the periphery. After the withdrawal of the guide wire, the catheter assumes a curved configuration, for instance, in the form of a pig tail. Withdrawal of the catheter then cuts the embolus into pieces. This process must be repeated several times and results in a relatively rough fragmentation of the embolus. By this maneuver, a lowering of the pulmonary arterial pressure was attained, and consequently the risk of heart attack and subsequent death was reduced.
This described technique for the fragmentation of pulmonary emboli is fairly complicated and protracted. Furthermore, this technique is very rough, as the pig tail catheters are not intended for fragmentation of a lung embolus.
One apparatus for the treatment of lung emboli known as a "Thrombolyseur" includes a rotating basket that is unfolded by centrifugal force for fragmentation of the embolic material. Thrombotic material in the blood flow path towards the lung is caught by the created whirl and mechanically fragmented. A problem with the Thrombolyseur is that contact between the basket treads and the arterial wall cannot be avoided and can lead to injury.
Another apparatus for the treatment of lung emboli is known as an "Impeller-Katheter" in which a rotor (impeller) is positioned in the center of a self-expanding, stationary protective basket.
A problem with both of these apparatuses is that each rotational body is driven through a flexible shaft positioned in the interior of a catheter by an external drive at 100,000 to 150,000 rpm. The high rotational speed results in high load on the material and makes these apparatuses prone to defects. Due to the complexity of both apparatuses, the risk of erroneous handling by an inadequately trained operator is significant.